The present invention relates to techniques for screening objects. More particularly, the present invention relates to techniques for screening (e.g., collecting, sampling, detecting, analyzing, etc.) objects for the presence of certain materials, such as controlled substances.
Controlled substances, such as explosives (e.g. C4, TNT, dynamite, fuels, chemicals, casted and/or other volatile materials), contraband (e.g. illegal drugs), chemical agents (e.g. toxins), etc., may pose a significant threat to persons and/or property. In an effort to prevent the unauthorized use or possession of such controlled substances, steps are often taken to locate target materials (e.g., materials used in connection with and/or incorporated in such controlled substances) before they can be used. Materials not used in connection with controlled substances may also be target materials. In many cases, such target materials may be hidden or stored to prevent detection, or are only present in small volumes.
Techniques have been developed in an attempt to detect the presence of certain target materials. Some techniques involve off-line laboratory analysis, such as monitoring environmental pollutants and in industrial hygiene monitoring. Other techniques involve on-line processes, such as detection systems used at checkpoints to interrogate personnel or vehicles for the target materials. Interrogation often involves the collection of materials from persons or objects using various collectors, such as volume, thin foil and membrane filters. Foam or other porous materials may be employed as described, for example, in U.S. Pat. No. 7,430,928, and in Grate, Anheier and Baldwin, Progressive Thermal Desorption Of Vapor Mixtures From A Preconcentrator With A Porous Metal Foam Internal Architecture And Variable Thermal Ramp Rates in Analytical Chemistry, Volume: 77, Issue: 6 (Mar. 15, 2005), pp. 1867-75.
Once the material is collected, it may then be released into small volumes for introduction into a detection system in a process known as pre-concentration. Techniques, such as pre-concentrators, have been developed for handling trace amounts of materials as described, for example, in US Patent/Application Nos. 20060271211, U.S. Pat. Nos. 6,948,325, 6,617,591, 6,477,907, 7,299,711, 6,345,545, 6,617,591, 6,604,406, 6,572,825, 6,523,393, 6,085,601, RE38,797, 5,854,431, 6,978,657, and 6,171,378. The pre-concentrated material may then be examined by a detector to determine if the target material is present. Detectors have been developed to identify the presence of explosive materials as described, for example, in US Patent/Application No. 20060271211, U.S. Pat. Nos. 6,978,657, 6,948,325, 6,617,591, and 6,477,907. Some techniques involve the use of handheld devices as described, for example, in U.S. Pat. Nos. 5,092,156 and 6,978,657.
Despite the development of techniques for collecting, pre-concentrating or detecting certain materials, there remains a need to provide advanced systems and methods for screening for such materials. It may be desirable to have techniques that perform integrated operations. It may further be desirable to provide techniques that enable screening of materials in a variety of locations and/or positions. Preferably, such techniques involve one or more of the following, among others: low cost design and ease of use.